外文翻譯-- 發(fā)動(dòng)機(jī)曲軸箱軸承座裂解加工數(shù)值分析

1、<p>　　畢業(yè)設(shè)計(jì)(論文)外文資料翻譯</p><p>　　學(xué)院 (系)： 機(jī)械工程學(xué)院 </p><p>　　專 業(yè)： 機(jī)械工程及自動(dòng)化 </p><p>　　姓 名： </p>

2、;<p>　　學(xué) 號(hào)： </p><p>　　外文出處：Numerical analysis on fracture Splitting technology of bearing block of engine </p><p>　　附 件： 1.外文資料翻譯譯文；2.外文原文。 </p><

3、p>　　注：請(qǐng)將該封面與附件裝訂成冊(cè)。附件1：外文資料翻譯譯文</p><p>　　發(fā)動(dòng)機(jī)曲軸箱軸承座裂解加工數(shù)值分析</p><p>　　預(yù)先精確計(jì)算裂解力參數(shù),對(duì)于裂解設(shè)備設(shè)計(jì)及工藝過(guò)程的制定至關(guān)重要。應(yīng)用MSC. MARC 軟件對(duì)捷達(dá)轎車發(fā)動(dòng)機(jī)主軸承座(以Ru T380 材料為例) 起裂過(guò)程進(jìn)行數(shù)值模擬,得出了裂解力與J 積分的關(guān)系曲線。根據(jù)J 積分值與斷裂韌性的關(guān)系,確定了臨

4、界J 積分,采用線性插值的方法獲得了裂解力,并進(jìn)行了實(shí)驗(yàn)研究。實(shí)驗(yàn)結(jié)果表明:此方法也適用于不同結(jié)構(gòu)、不同材料的其他分體類零件裂解加工時(shí)裂解力的確定。</p><p>　　裂解技術(shù)是分體類零件加工領(lǐng)域中一項(xiàng)新型加工工藝,其本質(zhì)是利用材料的脆性,在人為制造裂解源的前提下,通過(guò)外力使其斷裂,達(dá)到剖分體分離的目的,這就要求材料和結(jié)構(gòu)既要滿足零件的機(jī)械力學(xué)性能和使用壽命,又要適合裂解工藝的要求且要保證裂解質(zhì)量。汽車發(fā)動(dòng)機(jī)曲

5、軸箱軸承座的加工與連桿軸承孔的加工在結(jié)構(gòu)、工藝流程方面都適合于裂解工藝。發(fā)動(dòng)機(jī)缸體多采用優(yōu)質(zhì)灰鑄鐵、球墨鑄鐵、蠕墨鑄鐵等制造,都具有良好的脆性和機(jī)械加工性能,適合于裂解加工工藝并容易加工裂解槽。曲軸箱軸承座具有多個(gè)軸承孔結(jié)構(gòu),因此裂解設(shè)備需要具備裂解多個(gè)軸承孔的能力。所以發(fā)動(dòng)機(jī)曲軸箱軸承座較之連桿軸承孔更適合于裂解工藝,工藝更加復(fù)雜,效益更加明顯。作者應(yīng)用MSC. MARC 軟件對(duì)捷達(dá)轎車發(fā)動(dòng)機(jī)曲軸箱軸承座(以Ru T380 材料為例)

6、起裂過(guò)程進(jìn)行數(shù)值模擬,從而確定裂解加工中合適的裂解力參數(shù),并進(jìn)行了實(shí)驗(yàn)驗(yàn)證。</p><p>　　裂解加工的原理是通過(guò)在曲軸箱軸承孔中心處設(shè)計(jì)并預(yù)制缺口(初始裂紋槽) ,形成應(yīng)力集中,再主動(dòng)施加垂直于預(yù)定斷裂面的載荷進(jìn)行引裂,當(dāng)滿足發(fā)生脆性斷裂的條件時(shí),在幾乎不發(fā)生塑性變形的情況下,在缺口處規(guī)則斷裂,實(shí)現(xiàn)軸承座體與蓋的無(wú)屑斷裂剖分[5 ] ,如圖1 所示。由于斷裂面呈犬牙交錯(cuò)的自然形態(tài),具有極高的配合精度,無(wú)需加

7、工。在后續(xù)的軸承孔精加工及裝配過(guò)程中,分離后的蓋、體以斷裂剖分的三維曲面精確定位、自然嚙合、裝配。由于軸承座裂解后軸承座、蓋靠結(jié)合面裝配,結(jié)合面積大,承載能力提高,尤其是抗剪切能力大幅提高。由于結(jié)合面不用定位銷或定位套(平底式) 、或主軸承蓋兩側(cè)止口(龍門式) 定位,而是采用裂解結(jié)合面嚙合定位,定位精度和重復(fù)定位精度都很高,有效減小裝配時(shí)產(chǎn)生的圓度變形。裂解工藝使曲軸箱軸承座由分體加工變?yōu)檎w加工,省去了分離面拉削與磨削和止口加工等工序

8、,降低了加工成本,提高了經(jīng)濟(jì)效益。據(jù)德國(guó)大眾汽車公司計(jì)算及本課題組對(duì)連桿裂解的實(shí)驗(yàn)研究計(jì)算,就軸承座的裂解加工而言:1) 明顯減少設(shè)備投資30 %;2) 縮短生產(chǎn)線長(zhǎng)度,減少占地面積;3) 節(jié)省量輔具費(fèi)用40 %;4) 減少刀具種類,降低刀具</p><p>　　裂解技術(shù)的本質(zhì)是利用材料的脆性,在人為制造裂解源的前提下,通過(guò)外力使其斷裂達(dá)到蓋和體分離的目的。這就要求材料既要滿足曲軸箱軸承座的機(jī)械力學(xué)性能和使用壽命

9、,又要適合裂解工藝的要求且要滿足裂解的質(zhì)量。缸體多采用優(yōu)質(zhì)灰鑄鐵、球墨鑄鐵、蠕墨鑄鐵、鋁合金等制造,鑄鐵具有良好的機(jī)械加工性能,因此容易加工裂解槽?；诣T鐵抗拉性能遠(yuǎn)小于其抗壓性能,韌性低,因此具有良好的裂解性能,而且因其韌性低,裂解過(guò)程的塑性變形也小。球墨鑄鐵與灰鑄鐵相比. 主要優(yōu)點(diǎn)是有高的強(qiáng)度和韌性。蠕墨鑄鐵是在高碳、低硫和低磷的灰口鑄鐵澆注時(shí),向鐵水中加入蠕化劑(稀土鎂鈦合金等) ,使石墨形成短蠕蟲狀,蠕墨鑄鐵中的蠕蟲狀石墨形態(tài)是介

10、于球狀和片狀石墨之間的一種過(guò)渡型石墨,所以蠕墨鑄鐵的性能介于灰口鑄鐵和球墨鑄鐵之間。連桿多數(shù)用45 # 、45Cr 等中碳鋼或中碳合金鋼制成,抗拉強(qiáng)度和韌性都比鑄鐵材料高。因此從材料的角度看,裂解工藝更適合于鑄鐵材料的加工。</p><p>　　作為一種先進(jìn)的制造技術(shù),裂解工藝在國(guó)外各大汽車公司已不僅僅局限于連桿的制造與生產(chǎn),已經(jīng)得到了廣泛的推廣應(yīng)用。中外專家對(duì)發(fā)動(dòng)機(jī)箱軸承座裂解工藝作了大量研究工作。圖5a 和圖

11、5b 是國(guó)外研究機(jī)構(gòu)研究的裂解機(jī)構(gòu)原理圖裂解工藝在發(fā)動(dòng)機(jī)箱體加工中的應(yīng)用, 使原來(lái)分體加工的曲軸箱軸承座和軸承蓋改為整體加工, 由于裂解由多個(gè)環(huán)形截面部分沿軸向逐個(gè)排列的工件, 該方案包擴(kuò)1 個(gè)脹裂裝置,能夠沿軸向引入口內(nèi)作用于各個(gè)環(huán)形部件。該裂解裝置擁有1 個(gè)集中的脹裂控制裝置,通過(guò)控制裝置來(lái)調(diào)節(jié)脹裂的程度。工作原理是:通過(guò)軸向的驅(qū)動(dòng)裝置來(lái)調(diào)節(jié)推拉桿(圖4 中) ,使其產(chǎn)生相對(duì)運(yùn)動(dòng),將軸向驅(qū)動(dòng)力變?yōu)槊泬K(圖4 中) 的徑向擴(kuò)脹力,從而

12、達(dá)到裂解的目的。鑒于軸承座裂解加工工藝經(jīng)濟(jì)效益顯著,而且裝配性能好,德國(guó)的AL FIN G公司積極開展發(fā)動(dòng)機(jī)曲軸箱軸承座裂解加工設(shè)備的研發(fā)工作。2003 年AL FIN G公司提交第1 條全自動(dòng)曲軸箱軸承座的裂解加工生產(chǎn)線,并于2004 年4 月為德國(guó)大眾汽車公司建立了1 條發(fā)動(dòng)機(jī)箱體的裂解生產(chǎn)線[4 ] ,如圖6 所示?？梢妵?guó)外利用裂解加工工藝對(duì)曲軸箱軸承座進(jìn)行加工已經(jīng)成為研究熱點(diǎn),有</p><p>　　對(duì)鑄

13、態(tài)蠕墨鑄鐵Ru T380 進(jìn)行數(shù)值模擬和實(shí)驗(yàn)研究,其相關(guān)材料參數(shù)如下:彈性模量E = 1. 33×105 MPa ,泊松比μ= 0. 27 ,名義屈服應(yīng)力σ0. 2= 310 MPa ,抗拉強(qiáng)度σb = 400 MPa 。金相組織</p><p>　　三維實(shí)體造型是有限元數(shù)值模擬的基礎(chǔ),數(shù)值模擬的前處理階段需要輸入箱體的實(shí)體模型(或簡(jiǎn)化模型) 以形成邊界條件,根據(jù)發(fā)動(dòng)機(jī)箱體軸承座結(jié)構(gòu)及在裂解過(guò)程中的受力

14、特點(diǎn),捷達(dá)轎車四缸發(fā)動(dòng)機(jī)箱體軸承座的簡(jiǎn)化模型。公稱尺寸為:圓形孔直徑φ= 59 mm ,外端圓弧直徑為100 mm ,兩側(cè)寬度為100 mm ,兩螺栓孔間距為76 mm ,螺栓孔直徑為10 mm ,軸承座厚度為21 mm。裂解槽深度h = 0. 5 mm、張角2α= 20°、曲率半徑r = 0. 2 mm。根據(jù)發(fā)動(dòng)機(jī)箱體軸承座在裂解過(guò)程中的受力特點(diǎn),將模型簡(jiǎn)化分割,由于四缸發(fā)動(dòng)機(jī)箱體軸承座裂解過(guò)程是五個(gè)軸承座同時(shí)斷裂,各軸承座

15、受力特點(diǎn)相同,取其中之一進(jìn)行模擬分析即可。將 模型在裂紋槽對(duì)稱面進(jìn)行分割,由于軸承結(jié)構(gòu)左右對(duì)稱,故可略去原圖的一半,這樣進(jìn)行有限元模擬分析的三維零件圖就為原來(lái)的1/ 2 。由于箱體尺寸相對(duì)較大,裂解過(guò)程中固定不動(dòng),因此箱體下端采用完全固定約束,即:Ux = Uy= Uz = URx = URy = URz = 0 ,在箱體的圓弧對(duì)稱面上,由于結(jié)構(gòu)對(duì)稱、載荷對(duì)稱,因此對(duì)稱分割面上的點(diǎn)在X 方向無(wú)位移,即:Ux = </p>

16、<p>　　網(wǎng)格的劃分分為裂紋區(qū)與非裂紋區(qū),預(yù)先在模型上留出裂紋區(qū),然后在Marc/ metant 軟件中對(duì)非裂紋區(qū)進(jìn)行實(shí)體建模及網(wǎng)格劃分,采用127號(hào)8 節(jié)點(diǎn)四面體單元(見圖5 (a) ) 。然后,生成裂紋區(qū)實(shí)體模型,采用21 號(hào)20 節(jié)點(diǎn)八面體單元,由于裂紋區(qū)實(shí)際尺寸較小,放大的裂紋區(qū)網(wǎng)格。通過(guò)Glue 功能將非裂紋區(qū)與裂紋區(qū)的網(wǎng)格粘在一起,中心對(duì)稱面與非裂紋區(qū)用Touching 命令接觸連接, 最后激活I(lǐng)Dboundar

17、y conds 命令,完整的有限元網(wǎng)格模型及邊界條件如圖5 (d) 所示。對(duì)于彈塑性斷裂力學(xué),裂尖的應(yīng)力與應(yīng)變場(chǎng)產(chǎn)生1/ r 的奇異性,二維情況下,這種奇異性可通過(guò)帶有3 個(gè)重疊節(jié)點(diǎn)的三角形單元模擬,而對(duì)本文三維模型的分析,可采用20 節(jié)點(diǎn)塊體等參單元蛻化構(gòu)造奇異單元來(lái)模擬裂紋前緣的應(yīng)力場(chǎng)。</p><p>　　本文采用擴(kuò)展J 積分法即算法來(lái)計(jì)算裂紋的J 積分, 并通過(guò)拓?fù)渌阉髯詣?dòng)定義積分路徑。拓?fù)渌阉鞣ㄊ侵赋绦?/p>

18、首先自動(dòng)選取與裂紋尖點(diǎn)相聯(lián)系的所有單元的外輪廓線作為第一條積分路徑,然后進(jìn)一步搜索與第一條積分路徑相聯(lián)系的單元的外輪廓線作為第二條積分路徑,以此類推,可以較方便地確定積分路徑。分析中采用30 步分步加載,每步增量4. 6 KN。裂紋尖端節(jié)點(diǎn)共43 個(gè), J 積分路徑數(shù)目定義為6 個(gè), 裂紋尖端節(jié)點(diǎn)的允差設(shè)為0. 001mm。經(jīng)模擬分析得到了每個(gè)增量步裂解力對(duì)應(yīng)的所有裂尖節(jié)點(diǎn)的J 積分?jǐn)?shù)據(jù)。</p><p>　　為

19、了驗(yàn)證模擬分析的正確,在CSS288300 材料試驗(yàn)機(jī)上用專門設(shè)計(jì)的裝置(見圖8) 進(jìn)行了實(shí)驗(yàn)驗(yàn)證,設(shè)備最大公稱拉力為300 KN ,計(jì)算機(jī)的信號(hào)采集速率為200 次/ s ,實(shí)驗(yàn)溫度為室溫,速度為4 mm/ s。試件裂解槽尺寸為:裂解槽深度h =0. 5 mm、張角2α= 20°、曲率半徑r = 0. 2 mm。共實(shí)驗(yàn)3 件(見圖9) 。根據(jù)實(shí)驗(yàn),平均裂解力為137kN (圖10 為實(shí)驗(yàn)曲線之一) 。由計(jì)算可知,模擬值與試驗(yàn)

20、值的誤差為:</p><p>　　μ= (137 - 129. 32) / 137 ×100 % = 5. 6 %</p><p>　　由于J IC對(duì)應(yīng)的裂解力實(shí)際上是裂紋啟裂的裂解力閾值,即滿足預(yù)制裂紋槽啟裂的最小力。理論上,裂紋啟裂后能否快速擴(kuò)展直至斷裂,取決于裂紋擴(kuò)展時(shí)的彈性釋放能是否滿足裂紋擴(kuò)展對(duì)表面能的要求。如果彈性釋放能大于表面能,裂紋能夠自動(dòng)擴(kuò)展;反之,則必須提高外

21、力克服表面能,裂紋才能自動(dòng)擴(kuò)展?？梢娏呀饬_(dá)到裂解力閾值時(shí),未必能夠保證裂紋自動(dòng)擴(kuò)展,這由材料的性能所決定。因此,本文將達(dá)到裂解力閾值時(shí)的裂解力視為斷裂的裂解力( 即保證裂紋自動(dòng)擴(kuò)展的力) 與實(shí)驗(yàn)得到斷裂的裂解力結(jié)果進(jìn)行比較,無(wú)疑會(huì)帶來(lái)一定的誤差。液壓回路中的程序庫(kù)元件</p><p>　　圖12中的結(jié)構(gòu)圖是挖掘機(jī)模型圖形組成的液壓部分，以下的模型是從專屬的程序庫(kù)中選出，連接并輸入?yún)?shù)。注意到從Hylib來(lái)的缸和

22、馬達(dá)能簡(jiǎn)單連接為所示的多功能程序庫(kù)的組件。輸入信號(hào)如，挖掘機(jī)發(fā)動(dòng)機(jī)的相關(guān)信號(hào)由圖框給出。使測(cè)量孔的直徑具體化。如控制流體速度的參考閥。對(duì)于挖掘機(jī)的機(jī)械部分，只要圖12中所示的元件直接與液壓元件相連接。如液壓缸接觸的直線壓力元件。</p><p>　　曲軸箱軸承座裂解加工工藝是隨著汽車工業(yè)的發(fā)展而產(chǎn)生的一種新型加工工藝。應(yīng)用MSC.MARC 軟件對(duì)發(fā)動(dòng)機(jī)曲軸箱軸承座裂解過(guò)程進(jìn)行了數(shù)值分析,采用了20 節(jié)點(diǎn)塊體等參單

23、元蛻化構(gòu)造奇異單元來(lái)模擬裂紋尖點(diǎn)的奇異性,得出了裂解力與J 積分的關(guān)系曲線,根據(jù)Ru T380 材料的臨界J 積分值,確定了裂解加工所需的裂解力。實(shí)驗(yàn)表明:此方法適用于不同結(jié)構(gòu)、不同材料的其他剖分類零件裂解加工時(shí)裂解力的確定。為設(shè)計(jì)裂解設(shè)備及制定工藝參數(shù)提供了可靠的數(shù)據(jù),并奠定了堅(jiān)實(shí)的理論基礎(chǔ)。</p><p><b>　　附件2：外文原文</b></p><p>　

24、　Multi-Domain Simulation:</p><p>　　Mechanics and Hydraulics of an Excavator</p><p><b>　　Abstract</b></p><p>　　Precalculating precisely the parameters of t he splitting f

25、orce is significant for the design oft he splitting equipment and working out the technological process. MARC was used to simulate t he split ting process of t he main bearing block (it s material is vermicular graphite

26、as example) in car engines, and t he splitting force versus J2integral relationship was obtained. The critical J2integral value was determined from the J2integral versus fracture toughness relationship, and t he split ti

27、n</p><p>　　Pyrolysis technology is the split-type parts in a processing area of the new processing technology, its essence is the use of brittle materials, in the man-made sources of cracking under the premi

28、se of external force to break through to achieve the purpose of subdivision separated, which requires materials and structures it is necessary to satisfy the part of the mechanical properties and service life, but also t

29、he requirements for cracking process and to ensure that the quality of cleavage [122</p><p>　　Pyrolysis processing principle is crankcase bearing bore through the center at the design and pre-gap (initial cr

30、ack slots), the formation of stress concentration, and then take the initiative to put the scheduled fracture surface perpendicular to the load carried cited bifida, brittle fracture occurs when the meet the conditions,

31、almost no plastic deformation occurred in the circumstances, in the gap at breaking the rules to achieve bearing body and cover the non-chip fracture subdivision [5], </p><p>　　Pyrolysis is the essence of te

32、chnology, the use of brittle materials, in the man-made sources of cracking under the premise of external force to break through the cover and body to achieve the purpose of separation. This requires that materials it is

33、 necessary to meet the crankcase bearing the mechanical properties and service life, but also for cracking process and to meet the requirements of the quality of cleavage. Multi-cylinder high-quality gray iron, ductile i

34、ron, graphite cast iron, alumi</p><p>　　As an advanced manufacturing technology, pyrolysis process in foreign countries is not limited to the major automotive companies have manufacturing and production of c

35、onnecting rods, has been widely popularized. Chinese and foreign experts on the engine case bearing cracking process made a lot of research work [8, 9]. Figure 5a and Figure 5b is a foreign research institutions, researc

36、h institutions schematic cracking process in processing the application of the engine box, so that processing of </p><p>　　Pairs of cast vermicular graphite cast iron Ru T380 numerical simulation and experim

37、ental research, and its related material parameters are as follows: elastic modulus E = 1. 33 × 105 MPa, Poisson's ratio μ = 0. 27,nominal yield σ0. 2 = 310 MPa, tensile strength σ6 = 400 MPa. Microstructure<

38、/p><p>　　Three-dimensional solid modeling is the basis of finite element numerical simulation, numerical simulation of the pre-treatment phase of the solid model input box (or simplified model) to form the boun

39、dary conditions, according to the engine box bearing structure and in the pyrolysis process of the force characteristics of , four-cylinder engine Jetta box bearing the simplified model. Nominal size: round hole diameter

40、 φ = 59 mm, the outer end of arc in diameter 100 mm, on both sides of a width o</p><p>　　The division of the grid is divided into cracks and no-crack zone, pre-crack in the model area set aside, and then Mar

41、c / software crack area of non-physical modeling and meshing, using 8-node tetrahedron element, No. 127 (See Figure 5 (a)). Then, generate crack zone entity model, using 21, 20 nodes in octahedral unit crack area due to

42、the actual size of small, enlarge the crack area grid. Glue functions through the non-crack area and crack area grid stick together, the center symmetry plane and</p><p>　　In this paper, namely, expansion of

43、 J integral method algorithm to calculate the J-integral crack, and through topology discovery (Topology Search) automatically define the path integral. Topology search method refers to the program automatically selects

44、the first point associated with the crack tip for all units outside the contour line as the first integral path, and then the further search and the first integral paths linked to the outer cell contour points as the sec

45、ond path, and so on, can </p><p>　　In order to verify the correct simulation analysis, in the CSS288300 material testing machine with specially designed device (see Figure 8) for the experimental verificatio

46、n of equipment nominal maximum pulling force of 300 KN, the computer's signal acquisition rate of 200 times / s, test temperature at room temperature a rate of 4 mm / s. Tank size specimen cracking: cracking groove d

47、epth h = 0. 5 mm, spread angle 2α = 20 °, curvature radius r = 0. 2 mm. We can see from the calculation, simulat</p><p>　　μ = (137 - 129. 32) / 137 × 100% = 5. 6%</p><p>　　As J IC corr

48、esponding to cracking force is actually crack initiation of the cracking strength, that is to meet the pre-crack slots crack initiation of the minimum force. In theory, crack after rapidly expanding until the fracture, d

49、epending on the flexibility of the release of crack growth can be the satisfaction of crack propagation on the surface energy requirements. If the elasticity of the release can be greater than the surface energy, crack c

50、an automatically expand; the contrary, you need </p><p>　　Crankcase bearing cracker processing technology along with the development of automobile industry produced a new type of processing technology. Appli

51、cation MSC.MARC software engine crankcase bearing decomposition process of the numerical analysis, using 20-node degenerated is block units constructed to simulate the crack tip singular point of singularity, arrived at